docs: def form_valid(self, form):
          """ Handles a valid form. """
          user_kwargs = (
              {'voter': self.request.user}
              if self.request.user.is_authenticated
              else {'anonymous_key': self.request.user.forum_key}
          )
  
          if self.object.user_changes:
              # If user changes are allowed for this poll, all the poll associated with the current
              # user must be deleted.
              TopicPollVote.objects.filter(poll_option__poll=self.object, **user_kwargs).delete()
  
          options = form.cleaned_data['options']
          for option in options:
              TopicPollVote.objects.create(poll_option=option, **user_kwargs)
  
          return HttpResponseRedirect(self.get_success_url())